Questions tagged [power]
Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt (one joule per second). Use this tag where power is a primary concern for the design under discussion. Use the "low-power" tag when that applies.
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How can I calculate the power efficiency of an SMD LED? (% converted to light and % converted to heat)
I am designing an LED matrix for an LED lamp. I need to calculate the heat dissipation from all LEDs which is the dissipation of one LED times their number to choose an appropriate heat sink.
The ...
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How to estimate power dissipated in LDO from datasheet?
I'm doing a thermal analysis and need to estimate the worst-case dissipated power in this LDO. My thinking is to do this:
(input current * input voltage) - (output current * output voltage)
But ...
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Noise Reduction
I know how important it is to use capacitors to reduce noise in a DC circuit. I use them to ensure Vs is clean for any ...
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Explain this power management chip design
Why are the gates of the MOSFETs for one of the phases being driven by an intermediary driver IC, while the remaining phases are driven by embedded drivers? Why not drive all 3 in the same way (either ...
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How to select the closest spice model from the manufacturer series?
I dont have the MOSFET spice model for STD2N80K5. How should i be selecting the closest MOSFET model from the manufacturer list? Should i be looking for a match of Vds or Rds on or current rating? The ...
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Turning a lamp off and on at each press of a momentary push-button switch connected to ground
I have an electric scooter with a throttle that has a momentary power switch (normally open). The throttle hall sensor has three wires +5V, GND and signal. There is one additional wire for the power ...
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How can I get Current and Voltage from PV cell?
The PV cell can be modelled with a current source, a diode and 2 resistors.
The following is the equation for single-diode model for a PV cell.
Except I and V, every variables are constants like Iph = ...
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Can a stone resistor with low values withstand 240 A pulsed current (1 Hz, 200 μs, 24 V)?
Pretty much as in the caption. I'm building a high pulse current system for a PHD project, using the capacitor bank discharge method to get the current I want. The main problem right now is a resistor ...
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Powering an opamp with a reference voltage from a zener diode
I'm making a PSU so I need to create a Vdd for the DC-DC switcher I am using that will power the switcher whilst the auxiliary supply is offline.
I decided to use an opamp comparator to drive a P-...
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Why can't we say capacitive load deliver leading var?
A capacitive load absorbs leading reactive power, whereas a capacitor used for power-factor correction acts as a reactive source and delivers leading reactive power. In an over-excited synchronous ...
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Li-ion charging + rails on small PCB (TP5100, XL4015, 2S BMS) — safest path without PCB rework?
I’m working on a piece of portable audio electronics and I’m running into some charging and power supply issues.
Project:
• Small 3-board build: power, signal (5 V), amp (needs ~9 V).
• Battery: 2 ...
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Is the Current Leading or Lagging?
I have an unconventional circuit and cannot determine if the current is leading or lagging. This makes a profound difference in the power factor calculation and so I'm asking if anyone can identify.
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Op-amp's common mode voltage in differential and isolated input signals
In the circuit below, a switching signal (10 kHz) from V1, which has a differential voltage of 3.3 V, is isolated and fed into an op-amp configured as a differential amplifier.
My question is: will ...
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Bode Plot Analysis - Determine parameters
I'm designing a digital boost converter and need help analyzing this Bode plot. Could you please help me determine the following parameters:
Crossover Frequency
Phase Margin
Gain Margin
My conclusions ...
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How to rewire several buttons to get power from a single source? [closed]
I want to buy about 20 recordable buttons. Each button requires two AAA batteries. Instead of buying 40 batteries, I would like to somehow rewire the buttons, such that all of them can be powered by a ...
